1. Field of the Invention
This invention relates generally to wireless telecommunication. More particularly, it relates to display techniques in wireless applications that enable viewing by a user of a wireless device.
2. Background of the Related Art
Year by year, wireless devices such as cell phones have grown smaller and lighter. Along with this trend of miniaturization is the implementation of a display screen that is correspondingly small. The size of the display screen, and amount of memory within the wireless device, are often limiting factors in many applications. This is particularly true for applications running in a wireless device that attempt to display a map for a user.
When a map is displayed in a wireless device using a conventional application, typically a map somewhat larger than the size of the display screen is downloaded and displayed centered on the display. However, existing map display applications are a bit cumbersome to use on a wireless device, as they typically do not allow the user to fluidly pan around a map that is being displayed at the time.
For instance, FIG. 6 shows a conventional wireless device (e.g., a cell phone) 600 having an LED display 610 and an image 660 loaded for display thereon. Existing applications load a display image 660 that is at best just a little larger in memory than the displayable portion of the display image 650.
In such conventional applications, the loaded image 660 is centered on the display 610, with undisplayed, or cropped portions of the loaded image forming an overlapping border image area, e.g., a 30 to 50 pixel border area just outside the displayable portion of the image 650.
In many displaying applications, particularly those that display a map, it is desirable to allow panning by the user. Most often, direction or arrow keys on a keypad of the wireless device are operated to cause the relevant application to move the displayed image in a desired direction. When panning, the user can move the displayed image only up until the point at which the edge of the loaded image meets the relevant edge of the display 610. At this point, the panning operation pauses, and a new image is requested by the wireless device—all while the user waits for the download of a new image centered at the current point of the curser.
Conventional panning operations on wireless devices provide a pop up such as a progress bar that visually depicts the state of the downloading operation for the new image centered at the current location. At this point, until the new image is fully downloaded, conventional applications disallow most user operations while the new image is being downloaded to maximize efforts (and reduce time) in fetching the new image, which severely interrupts the user's experience of panning through the displayed image.
When the wireless device is finally ready to continue (which in a wireless society seconds can seem like forever), the previously loaded image is deleted from memory, and replaced with a new image centered at the current point of the cursor. No attempt is made to reuse the old, deleted image.
Thus, most existing applications load a single map image, somewhat larger in dimensions than the screen, and allow the user to pan to one of the edges. Up until this point the panning operation may be smooth, but when the user reaches the edge of the map the application will appear to freeze. Many times a pop-up with a progress bar and/or an hourglass is usually displayed indicating to the user that the wireless device is working, and the user waits for the next map image to be retrieved across the wireless network. The inventors of this application appreciated that this conventional approach results in a poor user experience with significant wait periods each time a loaded map edge is reached, and a new map display image requested to be viewed is loaded. If the map images are not cached, the user often has to wait again for display of the same map if they pan back to a location that they have already viewed.
There is a need for both more seamless panning as perceived by the user of a wireless device such as a cell phone, as well as to minimize the down time during which the user is not permitted to continue on with their mapping control while the image is being fetched.